(a) Technical Field
The present invention relates to a photocatalytic reactor. More particularly, it relates to a photocatalytic reactor and a method for treating gaseous pollutants using the same, which decomposes and removes gaseous pollutants such as volatile organic compounds (VOCs), odors, etc., as well as liquid pollutants using an environmentally friendly photocatalytic reaction.
(b) Background Art
With the rapid development of the global industry, the problem of environmental pollution has become more serious requiring strict regulations for pollution treatment. Moreover, the diversification in the types of pollution sources, and continued generation of new pollutants has created various approaches to more effectively solve the pollution problem.
A recently developed method includes a method for treating pollutants using a photocatalytic reaction, which is relatively unaffected by temperature, pH, etc., and does not require strict treatment conditions. Moreover, the method for treating pollutants using the photocatalytic reaction can use clean energy such as the light of the sun, etc., and thus has the advantages of being environment-friendly and energy efficient.
The currently used photocatalytic reaction will be discussed briefly below. When light energy from the sun or any other light source is applied to a photocatalyst, electrons and holes are generated in the photocatalyst and migrate to the surface of the photocatalyst. The electrons and holes migrating to the surface of the photocatalyst come into contact with pollutants to be treated and cause chemical oxidation-reduction reactions, thereby decomposing the pollutant molecules.
An organic pollutant decomposition device using the photocatalytic reaction is a nature-friendly pollution reduction device and has enormous potential for development, and thus the interest in the photocatalytic reactor has increased.
Conventional photocatalytic reactors are classified as a suspended photocatalytic reactor as shown in FIG. 1 and a fixed photocatalytic reactor as shown in FIG. 2.
The suspended photocatalytic reactor 10 is a device for decomposing liquid pollutants and, as shown in FIG. 1, comprises a light source 11 for supplying light energy, a photoreactive treatment tank 12 for accommodating a fluid 14 to be subjected to pollutant removal treatment such as wastewater, dye solution, etc., and a photocatalytic powder 13 introduced and dispersed into the fluid 14 to be treated in the photoreactive treatment tank 12.
The suspended photocatalytic reactor 10 can utilize much larger surface area of the photocatalytic powder 10 in the photocatalytic reaction and thus has the advantage of high treatment efficiency compared to the fixed photocatalytic reactor. However, the photocatalytic powder 10 is not fixed to gaseous pollutants such as volatile organic compounds (VOCs), odors, etc., during treatment. Therefore, treatment of gaseous pollutants is not possible with a suspended photocatalytic reactor 10.
The fixed photocatalytic reactor 20 is a device for decomposing liquid and gaseous pollutants and, as shown in FIG. 2, comprises a light source 21 for supplying light energy, a photoreactive treatment tank 22 through which a fluid 26 to be subjected to pollutant removal treatment, including gaseous pollutants such as VOCs, odors, etc., and liquid pollutants such as wastewater, dye solution, etc., passes, and a photocatalyst-coated tube 25 on which a photocatalyst is coated and fixed.
The photoreactive treatment tank 22 includes an inlet 23 through which the fluid 26 to be treated is introduced and an outlet 24 through which the fluid 26 being in contact with the photocatalyst is finally discharged such that the fluid 26 introduced through the inlet 23 is in contact with the photocatalyst fixed on the photocatalyst-coated tube 25 to be decomposed and then discharged through the outlet 24.
Since the photocatalyst is fixed on the photocatalyst-coated tube 25 in the fixed photocatalytic reactor 20, it is not necessary to recover the photocatalyst separately. Moreover, even in the case where a sealed space for maintaining the contact between the photocatalyst and the gaseous pollutants to be treated or the flow rate of the fluid 26 to be treated is small, it is possible to treat the gaseous pollutants. However, compared to the suspended photocatalytic reactor 10, the reaction area of the photocatalyst is limited to the coated area of the photocatalyst-coated tube 25. Thus, when liquid and gaseous pollutants having high flow rate and velocity are treated (e.g., in a factory), the reaction time between the photocatalyst and the gaseous pollutants is very short, which makes it difficult to treat the pollutants, thereby reducing the treatment efficiency.
The current invention addresses the current drawbacks by providing an apparatus to treat gaseous pollutants in an effective, efficient, and environmentally friendly manner.